I turn polar bears white

Question: I turn polar bears white
and I will make you cry.
I make guys have to pee
and girls comb their hair.
I make celebrities look stupid
and normal people look like celebrities.
I turn pancakes brown
and make your champagne bubble.
If you squeeze me, I'll pop.
If you look at me, you'll pop.

Can you answer the riddle?

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Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?